Table of Contents for

sendmail, 4th Edition

The hoststat command is a synonym for the -bh command-line switch. It causes sendmail to print its persistent host status and exit. Persistent host status is enabled with the HostStatusDirectory option (HostStatusDirectory on page 1037).

The output produced by this command begins with a heading such as this:

-------------- Hostname --------------- How long ago ---------Results---------

Then, for each host whose status it has saved, sendmail prints this information:

To illustrate, consider this output:

-------------- Hostname --------------- How long ago ---------Results---------
there.ufoa.edu                              00:00:51 250 f21IuJf8029510 Message acce
*books.oreilly.com                          07:43:39 250 f21KGlGS029512 Message acce
progr.rammers.com                           06:55:08 No status available
fbi.dc.gov                                  03:28:53 Connection refused

Here, the previous connections to there.ufoa.edu and books.oreilly.com were successful. The status for books.ora.com is currently being updated, hence the asterisk showing it is locked. The host prog.rammers.com shows no status because connection to it could not be made. The last example shows that the connection to fbi.dc.gov was refused by that host.

Note that the results are limited to 27 characters unless the -v command-line switch (-v on page 249) is also used. In that case, results are limited to 79 characters, thus providing more complete information.

The name mailq (a synonym for the -bp command-line switch) causes sendmail to print the contents of its mail queues and then exit (Printing the Queue on page 422).

Note that the location of the queues is set with the QueueDirectory option (QueueDirectory on page 1070). That location can be overridden from the command line, but if it is, sendmail might give up its special privileges (unless it was run by root).

The name newaliases (a synonym for the -bi command-line switch) causes sendmail to rebuild all the aliases database files, print summary information, and then immediately exit (Rebuild the Alias Database on page 478). In this mode the -v command-line switch (-v on page 249) is automatically implied, and sendmail runs in verbose mode.

The location of the aliases file is given in the configuration file with the AliasFile option (Alphabetized Options on page 970). That location can be overridden from the command line, but if it is, sendmail gives up its special privileges (unless it was run by root).

The name purgestat is a synonym for the V8.8 and later -bH command-line switch (-bH on page 234). It causes sendmail to clear (purge) all the host-status information that was being saved under the HostStatusDirectory option’s directory (HostStatusDirectory on page 1037). Clearing is done by removing all the directories under the HostStatusDirectory directory. Note that the HostStatusDirectory directory is not itself removed.

Beginning with V8.10, sendmail purges host-status information only for hosts that exceed the setting of the Timeout.hoststatus option (Timeout.hoststatus (V8.8 and later) on page 1103).

The name smtpd is a synonym for the -bd command-line switch (-bd on page 234). It causes sendmail to run in the background as a daemon, listening for incoming SMTP mail (Daemon mode (-bd) on page 20). This mode of operation is usually combined with the -q command-line switch (Periodically with -q on page 427) which causes sendmail to periodically process the queue.

When sendmail begins to run, it performs a preliminary scan of its command-line arguments. It does this because some actions need to be performed before the configuration file is read. The -d command-line switch is processed during the prescanning phase.

After the command-line switches are prescanned, but before they are processed in full, sendmail performs two important internal tasks.

Command-line switches are processed by sendmail as they appear in the command line, from left to right. The processing of switches ends when an argument is found that lacks a leading - character, or, beginning with V8, when a -- argument is found.

The fact that the configuration file is read after the command-line switches are processed can lead to some confusion. Some, but not all, command-line switches can overwrite some configuration file commands. Because there is no general rule, we describe the behavior of each item (such as macros and options) in a chapter dedicated to each.

The final step sendmail undertakes in processing its command line is gathering the list of recipients. Each recipient (or list of recipients if more than one is contained in a single command-line argument) is fully processed for delivery, and any error messages are printed before delivery is actually undertaken.

If sendmail is running in a mode that doesn’t require recipients, any list of recipients in the command line is silently ignored.

Can’t write a user’s file sendmail exit value

An exit value of EX_CANTCREAT (the value 73) means that an output file could not be written to. This error generally refers to a user-specified file rather than a system- or configuration-file-specified file. For example, an attempt to write to a file that has any execute bit set in its permissions can yield an error, as can writing to a file that has more than one link. Writing to a file that is not a regular file can cause an error if the SafeFileEnvironment option (SafeFileEnvironment on page 1084) is set. Note that for some problems that produce this error, sendmail won’t print an error message.

A configuration error sendmail exit value

The EX_CONFIG exit value (the value 78) means that a fatal configuration problem was found, but not necessarily while reading the configuration file. Failure of a delivery agent to function correctly can lead to this kind of failure.

Note that the EX_CONFIG error and EX_SOFTWARE error (discussed later) cause the local postmaster to get a copy of the message on the presumption that local errors can only be fixed locally.

A system I/O error occurred sendmail exit value

An exit value of EX_IOERR (the value 74) means that a serious operating system error occurred. This class of error relates mostly to disk I/O.

No problems, all was fine sendmail exit value

The EX_OK exit code (value 0) indicates that sendmail did its job and there were no errors.

Note that this should be the exit value of all the programs that sendmail runs when they succeed without errors. The following C-language code, for example, returns a random value:

main(  )
{
         ← need a" return 0 "or exit(0) here
}

A system resource error sendmail exit value

The EX_OSERR exit code (value 71) results from various operating system errors. In general, this exit value is accompanied by an error message describing the problem.

A critical system file failure sendmail exit value

The EX_OSFILE exit code (value 72) results when certain system files could not be opened and when certain system programs could not be executed.

An internal software error sendmail exit value

The EX_SOFTWARE exit code (value 70) indicates that a software error occurred. For example, when figuring out whether to speak SMTP, sendmail looks to see whether the $u sendmail macro is present in the A= equate for the selected delivery agent (The special case of $u in A= on page 740). If $u is absent, sendmail will speak SMTP. If sendmail was compiled without SMTP support (SMTP on page 144), the fork(2)'d child prints an error and exits with an EX_SOFTWARE exit code.

Note that the EX_CONFIG (discussed earlier) and EX_SOFTWARE errors cause the local postmaster to get a copy of the message on the presumption that local errors can only be fixed locally.

A recoverable error sendmail exit value

The EX_TEMPFAIL exit code (value 75) is returned by sendmail to indicate that a temporary error has occurred. Temporary errors mean that the mail message will be put in (or remain in) the queue for the present and another delivery attempt will be made later.

One example of this type of error occurs when looking up aliases via a network service, such as NIS. If all the servers are too busy to answer before a timeout, sendmail should temporarily queue the message and look up the aliases again later.

A resource is unavailable sendmail exit value

The EX_UNAVAILABLE error code (value 69) indicates that some system resource is unavailable—for example, if the body size of an incoming message is larger than the size limit imposed by the M= equate (M= on page 746).

Also, all delivery agent programs must be designed to return an exit value that is defined in <sysexits.h>. If a poorly designed delivery agent exits with some other value, sendmail will issue this error and consider the delivery to have failed.

A command was used incorrectly sendmail exit value

The EX_USAGE error code (value 64) means that a command or configuration line was used incorrectly.

Specify sendmail.cf versus submit.cf V8.12 and later

There are four ways that email messages can be submitted to sendmail by other programs. One way is with the -t command-line switch (-t on page 248). This causes sendmail to read the message on its standard input, and to parse the addresses from the header lines. Another way is with the -bs command-line switch (-bs on page 236), which causes sendmail to speak SMTP on its standard input and output. The third way is to specify recipients on the command line, and to feed sendmail the message on its standard input. The fourth way is to connect directly to sendmail’s MSA port (FEATURE(no_default_msa) on page 635).

For the -t and -bs forms of submission to behave like messages submitted via the MSA port, it is desirable to use a special configuration file. This -A command-line switch does just that. By following it with a c character, you tell sendmail to use a configuration file named submit.cf in place of the default configuration file. If the -A switch is followed by an m character, the default configuration file is used:

% /usr/sbin/sendmail -Ac            ← use submit.cf
% /usr/sbin/sendmail -Am            ← use sendmail.cf

If the -A switch is omitted, the choice of configuration file depends on the mode under which sendmail was run. That is, if it was run with a -t or a -bs, the behavior is that of -Ac. Otherwise, the behavior is that of -Am.

Note that this -A command-line switch can be used by ordinary users without causing sendmail to drop any special privileges.

The submit.cf file is installed automatically when you install sendmail.cf (The submit.cf File on page 66). A custom one can easily be created using the FEATURE(msp) (FEATURE(msp) on page 633).

Specify message body type V8.1 and later

MIME support in V8 sendmail has been coupled to ESMTP and the BODY parameter for the MAIL command. The BODY parameter is passed through as is to the delivery agent. Two special parameters are internally recognized by sendmail. They tell sendmail that the message body is either 7bit or 8bitmime. 7bit forces the high bit off. 8bitmime causes sendmail to leave the high bit unchanged. Both override any setting of the SevenBitInput option (SevenBitInput on page 1090).

When sendmail accepts a connection with another site for incoming mail, it has no way to determine from context whether it is dealing with MIME mail. To override any configured assumptions, you can use the -B command-line switch:

-B 7BIT
-B 8BITMIME

Case is unimportant (7BIT and 7bit both work). The 7bit causes the local sendmail to tell the remote sendmail (in ESMTP mode) that the message body should have the high bit stripped from every byte. Conversely, 8bitmime tells the remote sendmail to preserve the high bit of each byte.

The value given to this -B command line or received via the BODY parameter is stored in the ${bodytype} sendmail macro (${bodytype} on page 808).

Set operating mode All versions

The -b switch tells sendmail in what mode to operate. For example, sendmail can “become” a daemon listening for incoming SMTP connections, or it can run in a mode that tells it to simply print the contents of the queue and exit. The form of the -b switch is:

-bmode

If mode is more than a single letter, all but the first letter is silently ignored. If the mode is missing or not one of those allowed, sendmail prints the following error message and exits:

Invalid operation mode bad letter here

If the -b command-line switch is omitted altogether, the default mode becomes -bm (deliver mail and exit).

Beginning with V8.7 sendmail, the letter that selected the operating mode is assigned at startup to the ${opMode} sendmail macro (${opMode} on page 839).

Use ARPAnet/Grey Book protocols Not V8.1 through V8.6

In the distant past, mail messages on ARPAnet were sent by using the ftp(1) protocol. Because that protocol was never intended for use with email, many different departures were designed (“patched in”) to solve particular problems. That growing anarchy caused Jonathan B. Postel to design SMTP in 1982 and to document that protocol in RFC821 (updated to RFC2821). Since then, SMTP has replaced FTP as the Internet standard for email.

In the belief that sufficient time had passed for all sites to have adopted SMTP, the -ba mode was deemed obsolete and removed from V8.1 sendmail. It turned out that the British Grey Book protocol was based on FTP. To support that protocol, this -ba command-line switch was restored in V8.7 sendmail.

The -ba switch causes each line of a message to be terminated with a carriage-return line-feed pair instead of with a newline. This switch also forces sendmail to guess the sender from the message header, instead of parsing it from the envelope. The -ba switch should never be used outside of a Grey Book setting.

Prior to V8.14, this -ba switch would cause STARTTLS to fail. Beginning with V8.14, this switch now works correctly with STARTTLS.

Run as a daemon, but don’t fork V8.8 and later

The -bD command-line switch is almost exactly the same as the -bd switch. That is, it causes sendmail to run as a daemon, but unlike the -bd switch, it prevents sendmail from performing a fork(2) and thereby keeps sendmail in the foreground. The -bD switch also prevents detaching from the controlling terminal (as does the -d99.100 debugging switch, -d99.100 on page 574).

This -bD command-line switch allows sendmail to be run from a “wrapper” script—for example, to detect whether it died or was killed:

#!/bin/sh
SENDMAIL=/usr/sbin/sendmail
UCBMAIL=/usr/ucb/mail

if [ -f $SENDMAIL -a -f $UCBMAIL ]
then
        $SENDMAIL -bD -q1h
        echo ${SENDMAIL}, which should run forever, died \
                | $UCBMAIL -s "Sendmail died" root
fi

Note that the echo line will never be reached as long as sendmail continues to run. Also note that you will not be able to restart sendmail in the usual manner with a SIGHUP if you use this script.

Run as a daemon All versions

The -bd command-line switch causes sendmail to become a daemon, running in the background, listening for and handling incoming SMTP connections.^[107]

To become a daemon, sendmail first performs a fork(2). The parent then exits, and the child becomes the daemon by disconnecting itself from its controlling terminal. The -bD command-line switch can be used to prevent the fork(2) and the detachment and allows the sendmail program’s behavior to be observed while it runs in daemon mode.

As a daemon, sendmail does a listen(2) on TCP port 25 by default for incoming SMTP messages.^[108] When another site connects to the listening daemon, the daemon performs a fork(2), and the child handles receipt of the incoming mail message.

Purge persistent host status V8.8 and later

The -bH command-line switch causes sendmail to clear (purge) all the persistent host-status information that was being saved as a result of the HostStatusDirectory option (HostStatusDirectory on page 1037). Note that the HostStatusDirectory directory is not itself removed, but all the subdirectories under it are. The purgestat(1) (purgestat (V8.8 or Later) on page 223) command-line command is a synonym for this switch.

Note that beginning with V8.10, sendmail only purges host-status files that exceed the timeout set by the Timeout.hoststatus option (Timeout.hoststatus (V8.8 and later) on page 1103).

Print persistent host status V8.8 and later

The -bh command-line switch is a synonym for the hoststat(1) command-line command. It causes sendmail to print its persistent host status and exit. See hoststat (V8.8 and Later) on page 221 for a description of this output.

Initialize alias databases All versions

The -bi command-line switch causes sendmail to rebuild its aliases(5) databases and then exit. This switch is described in Rebuild the Alias Database on page 478. The name newaliases and the (obsolete) -I command-line switch are synonyms for this mode.

Be a mail sender All versions

The -bm command-line switch (the default) causes sendmail to run once in the foreground. A list of recipients is taken from the command line (unless the -t command-line switch is used), and the message is read from the standard input and delivered.

This is the mode MUAs use when they invoke sendmail on the user’s behalf. The sendmail program processes the recipients first, then the message header, then the message body. Usually, the envelope recipients are those on the command line. But if the -t command-line switch is also used, the recipients are taken from the message header. The envelope sender is more difficult to determine:

Print number of messages in the queue V8.12 and later

The -bP command-line switch causes sendmail to print the number of messages currently queued and then exit. See Print the Number of Messages in the Queue on page 425 for a full description of how to use this command-line switch.

Print the queue All versions

The -bp command-line switch is a synonym for mailq(3). See Printing the Queue on page 422 for a full description of how to use this command-line switch.

Run SMTP on standard input All versions

The -bs command-line switch causes sendmail to run a single SMTP session in the foreground over its standard input and output, and then exit. The SMTP session is exactly like a network SMTP session. Usually, one or more messages are submitted to sendmail for delivery.

This mode is intended for use at sites that wish to run sendmail with the inetd(8) daemon. To implement this, place an entry such as the following in your inetd.conf(5) file, and then restart inetd(8) by killing it with a SIGHUP signal:

smtp   stream  tcp   nowait  root /usr/sbin/sendmail sendmail -bs

With this scheme it is important to either use cron(3) to run sendmail periodically to process its queue:^[110]

0 * * * * /usr/sbin/sendmail -q

or run sendmail in the background to process the queue periodically by specifying an interval to the -q command-line switch’s interval (Periodically with -q on page 427):

/usr/sbin/sendmail -q1h

There are advantages and disadvantages to using inetd(8) instead of the -bd daemon mode to listen for and process incoming SMTP messages. The advantages are the following:

The disadvantages are the following:

In general, the inetd(8) approach should be used only on lightly loaded machines that receive few SMTP connections.

The -bs switch is also useful for MUAs that prefer to use SMTP rather than a pipe to transfer a mail message to sendmail. Depending on how it is configured, mh(1) can use this feature.

Rule-testing mode All versions

The -bt command-line switch causes sendmail to run in rule-testing mode. This mode is covered in detail in Chapter 8 on page 299.

Verify: don’t collect or deliver All versions

The -bv command-line switch causes sendmail to verify the list of recipients. Each recipient in the list of recipients is fully processed up to the point of delivery without actually being delivered. If mail can be successfully delivered to a recipient, sendmail prints a line such as one of the following:

name ...deliverable
name ...deliverable: mailer $# value, host $@ value, user $: value

The first form is that of pre-V8 sendmail. The second form began with V8.1 sendmail.

The name is the original recipient address after it has undergone aliasing and rule set rewriting. A local user’s name expands to the contents of that user’s ~/.forward file. A mailing list expands to many names (and produces many lines of output). The mailer, host, and user correspond to the triple returned by rule set 0 (The parse Rule Set 0 on page 696). If no $@ is returned, the host part is omitted from this output.

If the recipient cannot be delivered to, sendmail instead prints the following:

name ...reason

The reason the recipient is undeliverable can be explained by any of many possible error messages (such as “No such user”) that would prevent successful delivery.

The -bv switch also prevents sendmail from collecting any mail message from its standard input unless the -t command-line switch (-t on page 248) is also given.

Beginning with V8.12, the restrictexpand keyword for the PrivacyOptions option causes sendmail to drop special privileges when the -bv switch is specified by a user who is neither root nor a trusted user. This prevents ordinary users from reading ~/.forward files, :include: files, and private aliases (aliases found in aliases files that are not ordinarily readable). The restrictexpand keyword also prevents the -v switch from being used.

Freeze the configuration file Not V8

Prior to V8 sendmail, the -bz command-line switch caused sendmail to build (or rebuild) its frozen configuration file (now obsolete). The frozen configuration file was just a simple image of sendmail’s variables after it had read and parsed the configuration file. The purpose of the frozen file was to enable sendmail to start up more swiftly than it could when parsing the configuration file from scratch.^[111]

The -bz command-line switch is obsolete. If you use it with V8 and higher sendmail, you will see this error message:

Frozen configurations unsupported

Location of the configuration file All versions

The -C command-line switch tells sendmail where to find its configuration file. The form of the -C switch is:

-C path

With V8 sendmail, space between the -C and the path is optional. The path specifies the location of the configuration file. That location can be either a relative or a full pathname. If path is missing, the location becomes the file sendmail.cf in the current directory.

The -C command-line switch causes sendmail to internally mark the configuration file as unsafe. An unsafe configuration file prevents all but root from setting certain options and causes sendmail to change its uid and gid to that of the user that ran it. If it is used by someone other than the superuser (and not in the -bt rule-testing mode), the -OQueueDirectory=path switch should also be used to set the location of the queue directory. If that location is not changed, sendmail fails because it cannot chdir(2) into its queue directory.

Prior to V8, the -C command-line switch also prevented sendmail from “thawing” its frozen configuration file.

One practical use for this command-line switch might be as part of a make(1) file that is used to generate a cf file from your mc file. Consider, for example, that you maintain the mc source for your configuration file in a directory that is separate from the sendmail source directory. If such a directory were /usr/local/src/sendmail/cf, and if the sendmail source were located in /usr/local/src/sendmail/8.12.7, you could create a Makefile something like this in the cf directory:

M4=/usr/ccs/bin/m4                           ← for Solaris 5.4
CFDIR=../sendmail-8.12.7/cf/
MC_FILE=yourhost                             ← the base name of your mc file
SENDMAIL=/usr/sbin/sendmail                  ← where your sendmail is located
create:
        @echo building
        @$(M4) -D_CF_DIR_=$(CFDIR) $(CFDIR)m4/cf.m4 ${MC_FILE}.mc > ${MC_FILE}.cf
        @echo testing
        @$(SENDMAIL) -C${MC_FILE}.cf -bt < /dev/null > /dev/null;
install:
        mv /etc/mail/sendmail.cf /etc/mail/sendmail.cf.save
        cp ${MC_FILE}.cf /etc/mail/sendmail.cf

Thereafter, to generate and install a new configuration file you just run the following commands:

% cd /usr/local/src/sendmail/cf
% make
building
testing
% sudo make install
mv /etc/mail/sendmail.cf /etc/mail/sendmail.cf.save
cp yourhost.cf /etc/mail/sendmail.cf
%

As you gather more machines to administer, you can centralize many mc files in one place and update the configuration files with a single command.

Set HoldExpensive option to true Deprecated

The -c command-line switch is a synonym for the HoldExpensive option (HoldExpensive on page 1036).

As of V8, this command-line switch has been deprecated and might not be included in future versions. Note that -oc is still a legal form of shorthand that sets the HoldExpensive option to true.

Write debugging output to a file V8.13 and later

The -D command-line switch causes sendmail to redirect sendmail’s debugging output (The Syntax of -d on page 530) into a file for later examination. It is used like this, where file is the name of an existing or new file:

-D file

The -D command-line switch (if used) must precede all -d switches on the same command line. Otherwise, the following error will print and all debugging output will be printed to the standard output (possibly causing you to miss seeing the error):

-D file must be before -d

The file specified with -D must live in a directory that is writable by the user running sendmail. If the file does not exist, it will be created. If the file already exists, it will be silently appended to.

Extra care must be exercised when using the -D command-line switch when sendmail is run as root because the target file will be appended to, even if it is a symbolic link to an important file. For example, when /tmp/foo is a non-root owned symbolic link that points to /etc/passwd, the following command line, when run by root, will silently append debugging information to the /etc/passwd file:

# /usr/sbin/sendmail -D /tmp/foo -d0.1 -bt < /dev/null

Enter debugging mode All versions

The -d command-line switch causes sendmail to run in debugging mode. This switch is described in gory detail in Chapter 15 on page 530.

Japanese font conversion Sony NEWS only

The -E switch is reserved for the Sony NEWS adaptation of sendmail. It is ignored by the Berkeley release of V8 sendmail and produces no errors if used by that version.

Set the ErrorMode option’s mode Deprecated

The -e command-line switch is a synonym for the ErrorMode option (ErrorMode on page 1028).

The -e command-line switch is deprecated and might not be included in future versions. Note that -oe is still a legal form of shorthand that sets the ErrorMode option to true.

Set the sender’s full name All versions

The -F command-line switch specifies the full name of the sender, which is used in mail headers and the envelope. The form of the -F switch is:

-Ffullname
-F fullname

Space between the -F and the fullname is optional. If fullname is missing and the -F is the last argument, sendmail prints the following error and exits:

sendmail: option requires an argument -- F

If the -F is followed by any other switches, the following switch is taken as the full name.

When specifying the sender’s full name, be sure to quote any internal spaces or shell special characters. For example, for the C shell the following would be needed to specify the full name Happy Guy!:

"Happy Guy\!"

In the absence of this switch, sendmail finds the sender’s full name in any of several places. These are described in the section discussing the $x sendmail macro ($x on page 851).

The -F command-line switch is used by programs and shell scripts that send email. Consider the following administrative shell script that is run by cron(8) once per night:

#!/bin/sh
DISKUSE="du -s"
ARCHDIR=/admin/mail/lists
LIMIT=10
NOTIFY=root@localhost

# Run this nightly to detect an overgrown archive directory
BLOCKS=`$DISKUSE $ARCHDIR | awk '{print $1}'`
if [ $BLOCKS -gt $LIMIT ]; then
        echo $BLOCKS over $LIMIT in $ARCHDIR |\
        /usr/sbin/sendmail -F"DU Report by root" -f du-report $NOTIFY
fi

Here, in the full-name portion of the From: header, the delivered warning email message will include the notation “DU Report by root”:

From: "DU Report by root" <du-report@your.domain>

Set sender’s address All versions

The -f command-line switch^[112] causes sendmail to take the address of the sender from the command line rather than from the envelope or message header. The -f switch is used by UUCP software and by mailing list software. The form of the -f switch is:

-faddr
-f addr

Space between the -f and the addr is optional. If addr is missing, sendmail prints the following error message and ignores the -f switch:

sendmail: option requires an argument -- f

Multiple -f switches cause sendmail to print the following error message and exit:

More than one "from" person

The behavior of this switch varies depending on the version of sendmail you are running.

Prior to V8, the uid of the user specifying the -f switch must match one of the usernames given in the T configuration command. If they do not match, sendmail silently ignores the option and determines the sender’s address in the usual ways.

From V8.1 through V8.6, the T configuration command was eliminated. If the -f or -r switch was used, and if the p (privacy) option was given authwarnings, sendmail included an X-Authentication-Warning: header in the mail message. That header warned that the identity of the sender had changed.

Beginning with V8.7 sendmail, the T was reintroduced, but in a different form (Trusted Users on page 173). First sendmail checks to see whether the user specified by the -f is the same as the login name of the user running sendmail, as would be the case for mh(1). If they are the same, sendmail silently accepts the address. If they differ, sendmail looks to see whether the login name of the user running sendmail is in the class $=t. If it is, sendmail silently accepts the address. If not, sendmail checks to see whether authwarnings is set for the PrivacyOptions option (PrivacyOptions on page 1065). If it is, the following warning is logged and included in the outgoing message:

X-Authentication-Warning: login set sender to new name using -f

An example of one use for the -f switch can be seen in the previous section covering the -F switch.

Set gateway submission mode V8.10 and later

Use of the -G command-line switch indicates to sendmail that the message being submitted from the command line is for relaying, and is not an initial submission. This switch is primarily intended for use by the rmail(8) program, a part of the UUCP suite of programs. Mail received by UUCP is mail that did not originate at the local site. It is intended to be relayed outward to other sites, or to be delivered locally. Because mail received by UUCP is not the initial (therefore, local) submission of a message, sendmail needs to be more strict about what it will accept.

A message received with the -G switch specified will be rejected if the address is not fully qualified. The -G command-line switch also tells sendmail to perform no canonicalization on the address. Note that future releases of sendmail might reject improperly formed messages when this switch is specified.

Initial hop count Deprecated

A hop is the transmittal of a mail message from one machine to another. Many such hops can be required to deliver a message. The number of hops (the hop count) is determined by counting the number of Received:^[113] header lines in the header portion of an email message. The maximum number of allowable hops is compiled in for most versions of sendmail but is set by the MaxHopCount option with V8. When the hop count for a message exceeds the limit set by the MaxHopCount option (MaxHopCount on page 1046), the message is bounced. Ordinarily, the count begins at zero. The -h command-line switch is used to specify a beginning hop count.

The forms for the -h command-line switch are:

-hnum
-h num

Space between the -h and num is optional. If num is missing, sendmail prints the following error message and ignores that switch:

sendmail: option requires an argument -- h

If num begins with a character other than a digit, the offending text is printed:

Bad hop count (bad text)

The previous failure illustrates that the minimum hop count must be positive.

The -h switch was originally used by BerkNet to carry the hop count in the envelope. It currently has no application.

Synonym for -bi Deprecated

The -I command-line switch is a synonym for the -bi command-line switch and the newaliases name. It is obsolete but retained for compatibility with the delivermail(1) program (the precursor to sendmail).

The -I switch is deprecated and might not be included in future versions of sendmail. The -I switch is present only if sendmail was built with DBM defined.

Set the IgnoreDots option to true Deprecated

The -i command-line switch is a synonym for the IgnoreDots option (IgnoreDots on page 1038).

The -i switch is deprecated and might not be included in future versions. Note that -oi is still a legal form of shorthand that sets the IgnoreDots option to true.

Japanese font conversion Sony NEWS only

The -J switch is reserved for the Sony NEWS adaptation of sendmail. It is ignored by the Berkeley release of V8 sendmail and produces no errors if used by that version.

Syslog label V8.10 and later

Ordinarily, when sendmail logs a message with the syslog(8) facility, it does so using the name “sendmail.” For example, the first part of a typical syslog(8) entry might look like this:

Mar  1 11:30:48 your.host.domain sendmail[18754]: f21IUUxl018753: to=...

The name “sendmail” usually precedes the process ID number, which is set off in square braces.

Beginning with V8.10 sendmail, it is now possible to change the name used by sendmail when it logs into a new name of your choice. This is done by using the -L command-line switch. To illustrate, consider this line from a typical /etc/init.d/sendmail system startup file:

/usr/sbin/sendmail -bd -q30m;

At some sites, administrators prefer to run the listening daemon (the -bd) separately from the queue processing daemon (the -q30m). At such sites, the system startup file might be rewritten (in part) like this:

/usr/sbin/sendmail -Lsendmail-listen -bd;
/usr/sbin/sendmail -Lsendmail-queue -q30m;

Here, the listening daemon will log its messages using the name “sendmail-listen” and the queue handling daemon will log its messages using the name “sendmail-queue.”

Note that if users other than root or trusted users use this switch, it will cause sendmail to syslog(8) a message such as the following:

user uid changed syslog label

Define a sendmail macro on the command line V8.7 and later

The -M command-line switch is used to assign a sendmail macro a value. Note that prior to V8.8, only single-character sendmail macro names could be defined. The -M command-line switch is fully described in Command-Line Definitions on page 786.

Set the MeToo option to true Deprecated

The -m command-line switch is a synonym for the MeToo option. It is used to set that option to true. The -m command-line switch is fully described in MeToo on page 1051.

Note that as of V8.10, the default for the MeToo option is set to true. Also note that as of V8.12 sendmail, this command-line switch is now deprecated.

Specify DSN NOTIFY information V8.8 and later

The -N command-line switch causes sendmail to append the DSN NOTIFY command to the ESMTP RCPT command. For example:

RCPT To:<friend@other.site> NOTIFY=SUCCESS

Here, sendmail is requesting that the other site return notification of successful delivery.

The -N command-line switch also causes sendmail to behave as though it got the NOTIFY command when producing a local bounce message. That is, -N affects the other sites’ behavior on SMTP mail, and the local site’s behavior on local delivery.

Should the message be successfully delivered by a host that understands DSN, or by the local host, a return message will be sent to the sender. If either site is running V8.8 or later sendmail, that return message will look (in part) like this:

Date: Fri, 14 Dec 2007 08:11:43 −0800 (PST)
From: Mail Delivery Subsystem <MAILER-DAEMON>
Subject: Return receipt
Message-Id: <200712142144.f21IuJf8029510@other.site>
To: <you@your.site>
MIME-Version: 1.0
Content-Type: multipart/report; report-type=delivery-status;
        boundary="f21IuJf8029510.834702270/other.site
Auto-Submitted: auto-generated (return-receipt)

This is a MIME-encapsulated message

--f21IuJf8029510.834702270/other.site

The original message was received at Fri, 14 Dec 2007 08:11:43 −0800 (PST)
from other.site [204.255.152.62]

   ----- The following addresses had successful delivery notifications -----
friend (successfully delivered to mailbox)

The -N command-line switch tells the NOTIFY command what to include and thus tunes how notification will be handled. The form of the -N command-line switch looks like this:

-Nnever
-Nkeyword,keyword,...

The first form sets NOTIFY to be NEVER, meaning send no notification. The second form tells NOTIFY to specify notification based on one or more of three possibilities:

These keywords can be listed after the -N to set a combination of notification requests. For example:

-Ndelay,success

This tells sendmail to ask for notification if the message is successfully delivered or delayed but not to get notification if the message fails.

If an unknown keyword is listed, sendmail prints the following error message and ignores the bad keyword:

Invalid -N argument

If the -N command-line switch is omitted, notification policy is left to the other site. The usual default is failure (and possibly delay). On the local machine, sendmail acts as though both failure and delay were specified.

Don’t do aliasing All versions

The -n command-line switch prevents sendmail from changing local recipient addresses with aliases. The -n switch is fully described in Prevent Aliasing with -n on page 482.

Set multicharacter option V8.7 and later

The -O command-line switch is used to set a multicharacter configuration option from the command line:

-OLongName=value

The -O switch is described in detail in Command-Line Options on page 948.

Set a single-character option All versions

The -o command-line switch is used to set a single-character configuration option from the command line:

-oXvalue

The -o switch is described in detail in Command-Line Options on page 948.

Set protocol and host V8.10 and later

The $r sendmail macro ($r on page 842) holds as its value the protocol that is used in receiving a mail message (usually SMTP or UUCP). The $s sendmail macro ($s on page 844) holds as its value the name of the sending host. Some programs, such as UUCP, need to be able to set the values of these macros from the command line. The old way to set them looked like this:

-oMrUUCP -oMslady

Here, the M option sets $r to be UUCP and $s to be lady.

Under V8 sendmail, the setting of $r and $s has been simplified. A command-line single switch, -p, can be used to set them both:

-prval:sval

Here, the rval is the value assigned to $r, and the sval is the value assigned to $s. The two are separated by a colon. If the sval is omitted, the colon should also be omitted.

Quarantine an envelope V8.13 and later

The -Q command-line switch causes sendmail to quarantine an envelope. See The -Q command-line switch on page 440 for a full description in context with quarantining in general.

Process the queue All versions

The -q command-line switch causes sendmail to process its queue once or periodically, depending on its arguments. The -q switch is described in detail in Periodically with -q on page 427.

What DSN info to return on a bounce V8.8 and later

The -R command-line switch tells sendmail to include the DSN RET command with an ESMTP MAIL command:

MAIL From:<you@your.host> RET=full
MAIL From:<you@your.host> RET=hdrs

The RET command requests the receiving site to (or not to) include a copy of the original message body in the bounced mail notification. RET=full requests that both headers and the message body be returned. RET=hdrs requests that only headers be returned. The RET= command affects the receiving site only if it agrees to handle the DSN extension to ESMTP. In the absence of RET or remote DSN support, the receiving site is free to return the message body if it so desires.

For local mail, sendmail uses this -R command-line switch to determine how it will handle local bounces. Normally, sendmail includes everything (full) in a locally generated bounce. By using hdrs, you can restrict local bounces to only the header portions of the original message.

The RET, and hence this -R command-line switch, is useful in two circumstances:

The form of the -R command-line switch looks like this:

-R arg

Space between the -R and its argument is optional. The arg must be present and must be either hdrs (return only headers) or full (return the body too). If it is any other value, the following error is printed and the setting defaults to full:

Invalid -R value

The -R command-line switch can appear only once in the command line. If it appears multiple times, the second and subsequent appearances will result in this error message:

Duplicate -R flag

Beginning with V8.10, sendmail allows you to set a policy of not returning the body, regardless of what is requested by the sending site. You do this by setting the PrivacyOptions=nobodyreturn option (PrivacyOptions=nobodyreturn on page 1066).

Set sender’s address Deprecated

The -r command-line switch is a synonym for the -f command-line switch. This -r command-line switch is deprecated and might not be included in future versions.

Set the SaveFromLine option to true Deprecated

The -s command-line switch tells sendmail to set the SaveFromLine option (SaveFromLine on page 1085) to true. This -s command-line switch is deprecated and might not be in future versions. Note that -os is still a legal form of shorthand that sets the SaveFromLine option to true.

Set the QueueTimeout option Deprecated

The -T command-line switch causes sendmail to set the QueueTimeout option (QueueTimeout on page 1075) to the value specified. This -T command-line switch is deprecated (as is the QueueTimeout option) in favor of the Timeout option of V8.7 sendmail (Timeout on page 1097) and might not be included in future versions of sendmail. Note that -oT is still a legal form of shorthand to set the value of the QueueTimeout option.

Get recipients from message header All versions

The -t command-line switch causes sendmail to gather its list of recipients from the message’s header in addition to gathering them from its command line. The -t switch takes no arguments.

When this switch is specified, sendmail gathers recipient names from the To:, Cc:, and Bcc: header lines. It also gathers recipient names from its command line if any were listed. Duplicates are discarded, the Bcc: header is stripped, and the message is delivered.

The -t switch is intended for use by MUAs. It should never be specified when sendmail is run in daemon mode.

This is the initial MUA-to-MTA submission V8.8 through V8.11

The -U command-line switch is used to tell sendmail that this is the very first step in this email message’s submission.

From V8.8 through V8.11, this switch did nothing. Beginning with V8.12, this switch was eliminated, and the default behavior of sendmail was changed. Now sendmail presumes that any message’s submission is an initial submission unless the -G command-line switch is present.

Specify the ENVID string V8.8 and later

The -V command-line switch is used to specify the envelope identifier for the outgoing message. That identifier is called the ENVID and is part of the DSN extension to ESMTP. ENVID and the ${envid} sendmail macro are fully discussed in ${envid} on page 823.

The form of the -V command-line switch looks like this:

-Venvid
-V envid

Space between the -V and its argument is optional. The envid must be a legal ENVID identifier. If an illegal character is specified in envid, the following error is printed, and that declaration is ignored:

Invalid syntax in -V flag

Run in verbose mode All versions

The -v command-line switch tells sendmail to run in verbose mode. In that mode, sendmail prints a blow-by-blow description of all the steps it takes in delivering a mail message.

After the sendmail.cf file is parsed and after the command-line arguments have been processed, sendmail checks to see whether it is in verbose mode. If it is, it sets the HoldExpensive option (HoldExpensive on page 1036) to false and sets the DeliveryMode option to interactive (DeliveryMode=interactive on page 1006).

The -v switch is most useful for watching SMTP mail being sent and for producing expanded output when viewing the queue.

% /usr/sbin/sendmail -v you@someother.site < /dev/null
you@someother.site... Connecting to localhost via relay...
220 your.site ESMTP Sendmail 8.12.9/8.12.9; Sun, 7 Sep 2003 15:48:23 −0600 (MDT)
>>> EHLO your.site
250-your.site Hello localhost [127.0.0.1], pleased to meet you
250-ENHANCEDSTATUSCODES...etc.

050 <you@someother.site>... Connecting to someother.site. via esmtp...
050 220 someother.site ESMTP Sendmail 8.13.0/8.13.0; Sun, 7 Sep 2003 15:55:35 −0600
(MDT)
050 >>> EHLO your.site
050 250-someother.site Hello your.site [192.168.5.12], pleased to meet you
050 250-ENHANCEDSTATUSCODES
050 250-PIPELINING
050 250-8BITMIME
050 250-SIZE
050 250-DSN050 250-ETRN
050 250-DELIVERBY
050 250 HELP
050 >>> MAIL From:<you@your.site> SIZE=294
...etc.

define(`confPRIVACY_FLAGS',`noverb')    ←omit this
define(`confPRIVACY_FLAGS',`goaway')    ←omit this

Log transactions V8.1 and later

The -X command-line switch tells sendmail to open the file whose name is the next following argument and to append both sides of all SMTP transactions to that file. The -X command-line switch is described in full in Log Transactions with -X on page 512.

Note that this -X command-line switch causes sendmail to drop special privileges when run by an ordinary user.

Ignored OSF and AIX 3.x only

V8 sendmail prints an error if an illegal switch is specified (whereas other versions of sendmail silently ignore them). The mailx program that is supplied with OSF/1 and AIX issues an illegal -x switch. To keep sendmail from uselessly complaining under OSF/1 and AIX, that switch is specifically ignored. To get the same behavior with AIX under V8.1 sendmail, look for _osf_ in main.c and uncomment the code necessary to ignore that switch.